In this study, researchers examined SEER database data of outcomes of 19,028 women with breast cancer and severe mental illness.

Elderly patients with breast cancer and comorbid mental illnesses have higher rates of all-cause mortality and require assistance coordinating medical services, study findings published in the Journal of Clinical Oncology have shown.

Breast cancer and severe mental illness increase the rates of mortality and morbidity individually, but there is a paucity of data regarding the impact these 2 conditions may have on patients compositely.

For this retrospective study, researchers accessed data from the Surveillance, Epidemiology, and End Results (SEER)-Medicare database and evaluated the outcomes of 19,028 women with stage I to IIIa breast cancer and severe mental illness. Eligible patients had 1 inpatient or 2 outpatient claims of severe mental illness, such as bipolar disorder, schizophrenia, or other psychotic disorders, at least 3 years prior to their breast cancer diagnosis.

The follow-up period was 5 years after diagnosis, and survival outcomes were compared with patients without mental illness.

Approximately 3% of selected patients had a diagnosis of mental illness. Upon multivariate analysis, the cumulative incidence for all-cause mortality was 38.0% compared with 19.4% for patients with and without mental illness, respectively (P <.001), showing nearly a doubling of the all-cause mortality hazard.

The cumulative incidence of breast cancer-specific mortality was approximately 20% greater among patients with mental illness vs those patients without (7.2% vs 6.2%; P =.1223).

Patients with mental illnesses were also more likely to be tobacco users, had an average of 3 or more comorbid conditions, and a larger proportion of patients had later-stage disease at diagnosis compared with patients without mental illness.

The authors concluded that “more research is needed to determine models of coordination that work best to improve outcomes among patients with severe mental illness and to further elucidate the causal pathways between mental illness and reduced survival among patients with breast cancer.”

Researchers discovered that the likelihood of a poor prognosis was increased for cases of cancer diagnosed after screening mammography with negative results versus those diagnosed after mammography with positive results.